Hirose O, Shibata I, Kudou H, Samegai Y, Yoshizawa S, Ono M, Nishimura M, Hiroike T, Kageyama K, Sakano T
Institute of Animal Health, Chiba Prefecture, Japan.
J Vet Med Sci. 1995 Dec;57(6):991-5. doi: 10.1292/jvms.57.991.
Porcine reproductive and respiratory syndrome (PRRS) viruses were isolated from pig samples obtained from two farms characterized by an increased number of stillbirth and high mortality in new-born piglets (farm A), and respiratory distress with high mortality in weaning and growing pigs (farm B) in 1993, respectively. When primary specific pathogen-free piglets, 5-day-old or 13-day-old, were experimentally inoculated with the isolates, they showed clinical signs of depress, anorexia, pyrexia, diarrhea, sitting posture and periocular edema. Rate of the weight gain was reduced in the inoculated piglets compared with the non-inoculated pig. There were no apparent differences in clinical signs between the piglets inoculated with the virus samples derived from farms A and B. Microscopically, the most prominent changes observed in experimentally inoculated piglets were interstitial pneumonia, nonpurulent myocarditis and catarrhal lymphnoditis post inoculation day (PID) 28. Viruses were recovered from tissues collected from the inoculated piglets on PID 7 or 28. Furthermore, the viruses were continuously recovered from the sera from PID 7 to PID 28. Antibodies measured by indirect immunofluorescence assay to PRRS virus were first detected in sera on PID 14, and the antibody titer rose to 1:1280 on PID 28.
1993年，分别从两个猪场采集的猪样本中分离出猪繁殖与呼吸综合征（PRRS）病毒。其中一个猪场（A场）的特征是死胎数量增加且新生仔猪死亡率高，另一个猪场（B场）的特征是断奶仔猪和生长猪出现呼吸窘迫且死亡率高。当5日龄或13日龄的原代无特定病原体仔猪经实验接种这些分离株后，它们表现出抑郁、厌食、发热、腹泻、坐姿和眼周水肿等临床症状。与未接种的仔猪相比，接种仔猪的体重增加率降低。接种来自A场和B场病毒样本的仔猪在临床症状上没有明显差异。在显微镜下，接种后第28天（PID 28），在实验接种的仔猪中观察到最显著的变化是间质性肺炎、非化脓性心肌炎和卡他性淋巴结炎。在PID 7或28时，从接种仔猪采集的组织中分离到病毒。此外，从PID 7到PID 28，血清中持续分离到病毒。通过间接免疫荧光法检测的针对PRRS病毒的抗体在PID 14时首次在血清中检测到，且抗体滴度在PID 28时升至1:1280。
